It is the objective of the proposed research to gain a detailed understanding of the interaction of the anticancer antibiotic mitomycin C with simple nucleophiles and with oligonucleotides and thus ultimately with DNA. It is widely held that this antibiotic acts after reduction as a mono- and as a bifunctional alkylating agent of biological macromolecules and that reaction in the latter fashion can lead to the formation of cross-links between the two strands of DNA. The chemical nature of the mono-links and of the cross-links in DNA is not known. It is proposed to study the reactive sites of mitomycin C by determining the structures of compounds arising from the interaction in aqueous medium of reduced mitomycin C with nucleophiles such as bisulfite anion, mercaptides and amines. It is also proposed to undertake synthetic studies to prepare mitomycin analogs and to use these analogs to investigate the possible involvement of an acylated C6 hydroxymethyl group in alkylation, and to study the possible addition of reactive groups to mitomycin derivatives possessing a 9-9a double bond. It is furthermore proposed to investigate in detail the interaction of reduced mitomycin C with xanthosine monophosphate and, in studies with R17 viral RNA, the possible involvement of mitomycin C in phosphate triester formation. Finally, it is proposed to study the interaction of this antibiotic with the duplex structure d-(pGpC)xd-(pGpC)4 as well as other oligodeoxyribonucleotides which will serve as models for the interaction of mitomycin C with DNA. The proposed investigation will rely heavily on the use of radioactively labeled materials, on chemical synthesis to prepare mitomycin analogs, on the isolation of reaction products between mitomycin and nucleic acid material by various chromatographic techniques and by electrophoresis as well as on organic structure elucidation procedures with particular emphasis on mass spectroscopic techniques such as Californium plasma desorption mass spectroscopy that permit the analysis of highly polar compounds.